Show us amazingly long uptimes

I sometimes noticed for long uptimes (like more then a year), the uptime command shows an exclamation mark. However, I cannot find a threshold or even the code for the exclamation mark at http://git.savannah.gnu.org/gitweb/?p=coreutils.git;a=blob;f... -- does anybody have an idea about that?

Is the exclamation mark intended to warn the admin to reboot (since there might be an updated kernel, etc.), or does the system wow itself? ;-)

Once upon a time it was a mark of pride to have a long uptime. My record was six months plus one day. Why did I reboot? Because I needed to upgrade my system.

Then I realised that big uptimes were a bad sign, that they signified a system that hadn't been kept up to date and was vulnerable.

At Mark Williams, we had a z8000 prototype, still in pieces, sitting on a lab table, which was up for at least 180 days. It well may have been longer.